Fuel injector



Jan. 12, 1965 SHALLENBERG 3,165,264

FUEL INJECTOR Filed April 14, 1961 2 Sheets-Sheet 1 $1 4 .ZONF F 70 T lfi 22 20 [6 8 18 1 Fuel. TANK 1O Y Z /8a, 4 Z/ 4 /-1 x FUELTANK MCD'W Jan. 12, 1965 R. L. SHALLENBERG FUEL. INJECTOR 2 Sheets-Sheet 2 Filed April 14, 1961 ,QN mm an E mm Q mm @N mu United States Patent 3,165,264 FUEL INJECTOR Robert L. Shallenherg, Wheaten, llL, assignor to International Harvester Company, Chicago, Hll., a corporation of New Jersey Filed Apr. 14, 196i, Ser. No. 103,156 2 Ciaims. (Cl. 23988) This invention relates to fuel injector means for internal combustion engines and in particular relates to a hydraulically operated fuel injector for use in a diesel engine.

The invention affords servo-injection action with the present injector, such action being provided by a double diameter, reciprocal, pressure-amplifying power piston and chamber structure; for appropriate operation of this structure, the injector is primarily adapted to be supplied non-concurrently from, and to be operated in staggered relation in the cycle by, two separate fluid sources. The first source is a metered fluid source having alternating periods of pressure fluid transfer and non-transfer; during non-transfer, the metered fluid source actually releases pressure on the injector and allows a minor amount of back flow constituted by excess fluid. The second source affords high-pressure fluid, supplying motivating pressure to the pressure amplifying power piston and chamber structure.

More specifically, my invention provides an injector having: first and second inlets for the respective first and second fluid sources; a fluid nozzle discharge portion ;a drain discharge portion; first circuit means, including a small diameter, final pressure means of the pressure amplifying power piston and chamber, connecting the metered source fluid first inlet and the fluid nozzle discharge portion for conducting fluid of the metered fluid source to the nozzle discharge portion; second circuit means, including a large diameter, motivating pressure means of the pressure amplifying power piston and chamber, connected between the second inlet and drain discharge portion for alternately conducting the highpressure fluid from the second inlet to the large diameter means and conducting the fluid from the large diameter means to the drain discharge portion; valving in the first circuit means comprising a first valve between the first inlet and small diameter means and having an open positiontion for charging the small diameter means with metered fluid, and a closed position preventing the power piston and chamber from creating pressure in the fluid in the small diameter means without an attendant discharge injecting the fluid from the fluid nozzle discharge portion; and valving in the second circuit means comprising a second valve between the second inlet and the drain discharge portion and having an injection initiating position in which the high-pressure second inlet is connected to the large diameter means, and a drain-opening position in which the large diameter means is connected to the drain discharge portion and the high pressure is prevented from acting in the second circuit means.

The second valve just referred to comprises, in particular, a pressure operable shuttle valve having a longitudinally acting pressure area communicating with the pressurized, metered-source fluid inside the first inlet whereby said second valve, during the open position of the first valve, is positioned in the drain-opening position preventing high pressure from acting in the second circuit means, and, during the closed position of the first valve, the second valve is positioned'in the injection initiating posit-ion connecting'the second inlet and the large diameter means. I V i It is therefore an object of my invention to provide a fluid consuming nozzle of which the consumed fluid intake is. supplied bytwo separate sources and in which ice there is provided a double diameter, reciprocable, pressure amplifying power piston and chamber mechanism affording servo-injection action.

Still another object is to provide a fuel injector including a servo-valve mechanism responding to fluid pressure from a metering source with subsequent high hydraulic fluid pressure injection.

A further object of this invention is to provide a fuel injector comprising a servo-injection mechanism subjected to fluid pressure from a metered quantity of fuel for operation of said mechanism pursuant to the introduction of fluid under high pressure to perfrom a fuel injection stroke.

Another object is to provide a source of metered fluid pressure to actuate a servo-injection mechanism with concurrent introduction of fuel to the associated fuel injection nozzle, and a source of high pressure for operating the servo-injection mechanism to expel the fuel in the fuel injection nozzle when the source of metered fiuid pressure is removed.

These and other object sof this invention will become apparent from a reference to the following disclosed drawings and description which illustrate an embodiment that the invention may take, such embodiment, however, is not to be construed as a limitation upon the breadth or scope of the appended claims, wherein:

FIGURE 1 is a schematic view illustrating an internal combustion engine having a servo-injection system employing the fuel injector;

FIGURE 2 is a diagrammatic view of the fuel injection system illustrating the sources of pressure for operation of the fuel injector;

FIGURE 3 is a view, partly in section, of the fuel injector shown in FIGURES 1 and 2; and

FIGURE 4 is a view of a diagram illustrating the relation between hydraulic fluid pressure and time of injection employed in the novel fuel injector; and

FIGURE 5 is a view partly in section of a modified version of injection nozzle assembly employed in the novel fuel injector.

With reference now to the drawings, there is shown an internal combustion engine 1 of the diesel type carrying a fuel injection system 2 including a fuel tank 3 with fuel tank outlet line 4 having divided flow through branch 5 to housing 6 carrying primary pump 7 and metering pump 8, and branch 9 carrying the fluid or fuel 10 to the high pressure supply pump 11. The metering pump 8 may be of a rotary distributor type fuel injection pump for supplying a metered quantity of fuel to the fuelinjectors 16 under pressure in a conventional manner having alternating periods of delivery and non-delivery of fluid under pressure thereto. The fiuid or fuel 10 thus may pass through the condit 18 into the injectors 16 or through the line 18a to the tank. A low pressure or fuel return line 19 communicates the fuel tank 3 with each of the six fuel injectors 16 to each of their respective conduits 20. Similarly, fuel line 21 communicates fluid under high pressure from the supply pump 11 to each of the injectors 16 through each of the high pressure inlet lines 22 of each of the injectors 16.

Reference is now directed in particular to FIGURE 3 wherein there is shown a fuel injector 16 comprising a body or housing 23 having a servo-injector mechanism or servo-valve mechanism 24 at its right end and a nozzle assembly 25 at its left end and a metering passage 26 within the servo-injection portion 24 communicating with the left end 27 of the pilot or shuttle valve chamber 23a and the metering line 18 land with the check valve chamber 29 in the injection nozzle assembly 25. The shuttle valve chamber 28a has a shuttle valve or pilot valve 28 reciprocally disposed therein having a first land or head portion 39 disposed against the end 27, as shown in FIG- URE 3, and a second land portion 31, a reduced portion 32 between the lands 30, 31 and a reduced extension 33 projecting from the right end of land 31 against a collar 34 retaining a spring 35 about an extension 36 of the servo-injection mechanism 24 in chamber 37 communicating with drain line 38 and fuel return line 2%) and also communicating With drain lines 38 4t 41 and to annulus 42 of chamber 28a. The chamber 28a also has an annulus 43 communicating with high pressure line 22 by way of line 22a and another annulus 44 communicating with a passage 45 into the power piston cham-- ber 46 at the left end 47 thereof. The piston chamber 46 has an enlarged portion 46a receiving an enlarged power piston portion 48 and a reduced injection portion 46b receiving a reduced piston portion 49, the piston portions 48 and 49 comprising a power piston 5t). Proxi mate the juncture of the reduced portion 46b and the enlarged portion 46a of the chamber 46 there is a drain line 51 communicating with drain line 41 and the reduced piston portion 49 may be separate from the piston element 48 and it has a dished out portion 52 to prevent interference between the power piston 5i) and the head 2% of the check valve 2% reciprocable within the check valve chamber 29, the check valve 29a having an enlarged right end head portion 290 reciprocable within enlarged chamber portion 29d of check valve chamber 29, the enlarged head portion 29c having a passage 2% communicating the metering passage 26 'with the right and left end portions 29 and 29g of chamber 29, and the left end head portion 29b forms a valve seat 53 with the extreme left end of the chamber portion 29g when the spring 29h in the enlarged chamber portion 29d urges the collar or right head portion 290 to the right asseen' in FIGURE 3.

Fuel injection nozzle passages 54 and 55 communicate the right end (FIGURE 3) of injection piston chamber 46b, into which projects check valve left end head 29b,-

with the enlarged nozzle annulus 56 of the nozzle injection chamber 57 into which projects shoulder 58 of theenlarged portion 59 of nozzle stem 60 which has a reduced end portion 61 having an end valve seat 62 with the nozzle housing 63 and has a right end stem portion 64 receiving collar 65 held thereon by collar spring 66a about projection 66 of the nozzle structure 25, the right end of extension 64, the collar 65, thespring 66a and the projection 66 all being housed within the cavity 67 of the nozzle injection assembly 25.

Operation FIGURE 3 shows the shuttle valve 28 in its extreme left position as urged by spring 35 just before the begin ning of the metering stroke with annulus 44 in communication with high pressure annulus 43 and high pressure.

lines 22a and 22 and 21. As the metering pump 6 begins its metering stroke a metered quantity of fuel under pressure is sent along lines 18 and 26 moving pilot valve 23 against spring 35 until it rests against stop 36 whereby land 30 blocks offcommunicationof the cham ber 28a to high pressure lines 220, 22 and 21 and places annulus .44 in communication with drain annulus 42 and drain lines 38 and 2! back to the reservoir or fuel tank 3. Asthe metering pressure continues to build up the metering fluid which passes into check valve chamber 29 unseats check valve head 2% allowing the fluid 10 to pass into the chamber at right end of'46b, moving pis-- ton assembly St to the left adesired distance, and as the I metering pump reaches the end of its metering stroke a relief position in the metering pump is attained sending the fuel by way of line 18a to the tank 3. The pressure falls ofl rapidly on theleft side of pilot valve 28, closing check valve 29, the spring 35' returning the valve- 28 to its left position as viewed in FIGURE 3. In this position of the valve 28, fiuid from the highfpressure l nes 21, 22 and 22a flows through the valve, the anll sv and pa g 45 t the extreme left side. 47

of chamber 46. Fluid in'the chamber 46 urges the piston portions 48, 4b to the right under high pressure compressing the metered fuel in lines 54 and .55 and right end of piston chamber 46b with extremely high pressure. Fluid delivered through'the passage 55 causes the nozzle shoulder 56 of nozzle. 60 to move to the right against spring 66a causing'the nozzle stem 61 to leave its seat 62 and allowing the fluid it) from the passage 55 to be injected out of the nozzle orifice 70 into the combustion chamber 71 of the cylinder 72 at an. extremely high rate of injection (curve II, FIGURE 4).

It will be noted that the high pressure fluid delivered to the element 46a has its effect doubled in lines 54' and 55 because of the reduced diameter of the power piston portion 46b. For example, if 10,000 pounds/sq. in. of fluid pressure is sent from the high pressure source 11 through line 45 then 20,000 pounds/Sc pio. of pressure is developed in right end of power pistonchamber portion 46b and lines 54, 55 and nozzle annulus 57 to unseat the nozzle valve 60. I

Thus it is seen that the metering pump 6 controls the cycle of fuel injection for during the metering stroke, the metering fuel under pressure moving the shuttle valve 28 to close the high pressure source 11 and at the same time to fill the check valve chamber and then unseat check valve 29a metering a charge to the nozzle assembly 25, and termination of the metering stroke allowing the shuttle valve 28 to return, and atthesame time allowing the check valve 29a toseat terminating the 'flow of metered fuel to. the chamber portion 46b and allowing fluid under high pressure to move power piston 46' for injecting the fuel 10 under high pressure into the combustion chamber 71, whence the cycle is repeated.

FIGURE 5 is a modified .form of a nozzle structure whereby the collarbS, the spring 66a and the stop 66 and the plunger stem 64 of a nozzle 6%? have been removed from the nozzle cavity 67 and the cavity 67 has an extension passage a communicating it directly with high pressure line 22a. By this construction the high pressure fluid is emitted directly into the nozzle cavity-67 to hold the nozzle valve 60 against its seat 62. By this construction,

fluid from thehigh pressure source 11 holds the nozzle valve 60 on its seat 62 and will only unseat when the high pressure fluid delivered to lines54 and 55 exceed the pressure in the cavity 67. In the applicants device this is possible since the high pressure in the cavity 67 isone half or of the high pressure in lines 54 and because of the area. of reduction of piston portion 46b relative to the power piston portion 46a.

What is claimed is: 1. In an injection system for an engine, said system having a servo-injection action and including a double diameter, reciprocal, pressure amplifying power piston and chamber mechanism: a a 7 an improved injector having first and second fluid in lets, said first inlet. comprising a metered fluid source inlet having alternating periods of pressure fluid transfer and non-transfer thereto,"said second inlet comprising a high-pressure supply inletgi i a fluid nozzle discharge portion; a draindischarge-portion; I

j first circuit means, including a small diameter, final valvingz in the first'circuit' means comprising a. first.

valving in the second circuit means comprising a second valve between the second inlet and the drain discharge portion and having an injection initiating position in which the high pressure of the second inlet is communicated to the large diameter means, and a drain-opening position in which the large diameter means is connected to the drain discharge portion and the high pressure is prevented from acting in the second circuit means; said second valve comprising a pressure operable shuttle valve and having a longitudinally acting, pressure area communicating with the pressurized, meteredsource, fluid inside the first inlet whereby said second valve, during the open position of the first valve, is positioned in drain-opening position preventing high pressure from acting in the second circuit means, and,

if during the closed position of the first valve, said second valve is positioned in the injection initiating position connecting the second inlet and the large diam eter means.

2. The invention of claim 1, said valving in the first circuit means further comprising a third valve between the small diameter means and the fluid nozzle discharge portion, said third valve cooperating with the first valve whereby the final pressure created in the fluid in the small diameter means causes a discharge injecting the fluid from the fluid nozzle discharge portion, said third valve being positioned in an open position by the final pressure resulting when the second valve is in the injection initiating posi tion, and having a closed position when the second valve is in the drain-opening position.

References (Iited in the file of this patent UNITED STATES PATENTS 2,138,849 Gambrell Dec. 6, 1938 2,598,528 French lWay 27, 1952 2,803,234 Mansfield et al. Aug. 20, 1957 2,816,533 Reggio Dec. 17, 1957 2,886,023 Holley et al. May 12, 1959 2,916,028 Mansfield Dec. 8, 1959 

1. IN AN INJECTION SYSTEM FOR AN ENGINE, SAID SYSTEM HAVING A SERVO-INJECTION ACTION AND INCLUDING A DOUBLE DIAMETER, RECIPROCAL, PRESSURE AMPLIFYING POWER PISTON AND CHAMBER MECHANISM; AN IMPROVED INJECTOR HAVING FIRST AND SECOND FLUID INLETS, SAID FIRST INLET COMPRISING A METERED FLUID SOURCE INLET HAVING ALTERNATING PERIODS OF PRESSURE FLUID TRANSFER AND NON-TRANSFER THERETO, SAID SECOND INLET COMPRISING A HIGH-PRESSURE SUPPLY INLET; A FLUID NOZZLE DISCHARGE PORTION: A DRAIN DISCHARGE PORTION; FIRST CIRCUIT MEANS, INCLUDING A SMALL DIAMETER, FINAL PRESSURE MEANS OF A PRESSURE AMPLIFYING POWER PISTON AND CHAMBER, CONNECTING THE FIRST INLET AND FLUID NOZZLE DISCHARGE PORTION FOR CONDUCTING FLUID OF THE METERED FLUID SOURCE TO THE FLUID NOZZLE DISCHARGE PORTION; SECOND CIRCUIT MEANS INCLUDING A LARGE DIAMETER, MOTIVATING PRESSURE MEANS OF THE PRESSURE AMPLIFYING POWER PISTON AND CHAMBER, CONNECTED BETWEEN THE SECOND INLET AND THE DRAIN DISCHARGE PORTION FOR ALTERNATELY CONDUCTING THE HIGH-PRESSURE FLUID TO THE LARGE DIAMETER MEANS AND CONDUCTING THE FLUID FROM THE LARGE DIAMETER MEANS TO BE DRAIN DISCHARGE PORTION; VALVING IN THE FIRST CIRCUIT MEANS COMPRISING A FIRST VALVE BETWEEN THE FIRST INLET AND SMALL DIAMETER MEANS AND HAVING AN OPEN POSITION FOR CHARGING THE SMALL DIAMETER MEANS WITH A METERED QUANTITY OF FLUID, AND A CLOSED POSITION PREVENTING THE POWER PISTON AND CHAMBER FROM CREATING FINAL PRESSURE IN THE FLUID IN THE SMALL DIAMETER MEANS WITHOUT AN ATTENDANT DISCHARGE INJECTING THE FLUID FROM THE FUEL NOZZLE DISCHARGE PORTION; AND VALVING IN THE SECOND CIRCUIT MEANS COMPRISING A SECOND VALVE BETWEEN THE SECOND INLET AND THE DRAIN DISCHARGE PORTION AND HAVING AN INJECTION INITIATING POSITION IN WHICH THE HIGH PRESSURE OF THE SECOND INLET IS COMMUNICATED TO THE LARGE DIAMETER MEANS, AND A DRAIN-OPENING POSITION IN WHICH THE LARGE DIAMETER MEANS IS CONNECTED TO THE DRAIN DISCHARGE PORTION AND THE HIGH PRESSURE IS PREVENTED FROM ACTING IN THE SECOND CIRCUIT MEANS; SAID SECOND VALVE COMPRISING A PRESSURE OPERABLE SHUTTLE VALVE AND HAVING A LONGITUDINALLY ACTING, PRESSURE AREA COMMUNICATING WITH THE PRESSURIZED, METEREDSOURCE, FLUID INSIDE THE FIRST INLET WHEREBY SAID SECOND VALVE, DURING THE OPEN POSITION PREVENTING HIGH POSITIONED IN DRAIN-OPENING POSITION PREVENTING HIGH PRESSURE FROM ACTING IN THE SECOND CIRCUIT MEANS, AND, DURING THE CLOSED POSITION OF THE FIRST VALVE, SAID SECOND VALVE IS POSITIONED IN THE INJECTION INITIATING POSTION CONNECTING THE SECOND INLET AND THE LARGE DIAMETER MEANS. 